Dbx 676 Owner’s Manual

Loading ...

676

Parallel Compression

Compression is typically applied as a serial process – meaning the entire signal is processed by the compressor. This is

sometimes referred to as ‘downward compression’. By applying make-up gain, the compressed signal can then be raised to

restore the signal’s average level to what it was before applying compression, hence the term ‘make-up gain’. Raising the

make-up gain also raises signal levels which reside below the compressor’s threshold, effectively raising lower-level portions

of the program signal and making them more audible in the mix. Using compression in this manner is very effective for most

applications, but there are times you may want the compression to be less obvious or you don’t want to trample on the original

transients and tone of the source, but still want to raise the lower-level portions of the signal. This is where the stealthier

parallel compression comes in.

Reverb and delay effects are generally applied as a parallel effect (more commonly known as a ‘send/return’ effect, or simply

‘send’ effect) – meaning that the signal is split, one signal is processed, then the processed signal is mixed back in with

the unprocessed signal. Parallel compression works the same way – the signal is split, one signal is compressed, then the

compressed signal is mixed back in with the uncompressed signal (see below diagram).

Parallel compression is a very common technique used in today’s audio production. It is a particularly popular technique for

drums, vocals, and acoustic guitar, but it can be used on anything. When applying parallel compression, the idea is to have the

compressed version of the signal disappear into the background as full compression is applied (typically 20 dB or more) –

this leaves the original sound virtually unchanged as the compressed signal is reduced below the point of audibility. When the

program signal level falls back below threshold, the severely compressed signal will begin to raise in level as the compressor

releases. This allows the lower-level detail in the program signal to be raised without compromising the tone and transients of

the original sound. This technique is also commonly used with more characterful compressors (this is very common on drums

and vocals and is commonly known as the ‘New York Compression Trick’).

The 676 has two outputs which can be used simultaneously to provide parallel compression capabilities. These two outputs

are the PREAMP and COMPRESSOR / LIMITER outputs. The COMPRESSOR / LIMITER output carries the signal post the

compressor/limiter processing. The PREAMP output carries the signal post EQ and before the compressor/limiter processing.

By using both outputs simultaneously, you can compress the signal coming out of the COMPRESSOR / LIMITER output and

recombine it with the uncompressed signal coming from the PREAMP output at the mixer or DAW as shown in the below

diagram.

PARALLEL COMPRESSION DIAGRAM

Compressed Signal

Combined Processed Signal

Uncompressed Signal

676

Ch.1

Gain Fader

(Mixer or DAW)

Ch.2

Gain Fader

(Mixer or DAW)

Loading ...

Dbx 676 Tube Microphone Preamp Channel Strip